Rt. Loeber et Da. Yurgelun-todd, Human neuroimaging of acute and chronic marijuana use: Implications for frontocerebellar dysfunction, HUM PSYCHOP, 14(5), 1999, pp. 291-304
Citations number
72
Categorie Soggetti
Neurosciences & Behavoir
Journal title
HUMAN PSYCHOPHARMACOLOGY-CLINICAL AND EXPERIMENTAL
The effects of cannabis use on the human brain are not well understood. Rec
ently neuroimaging research has begun to address the question of metabolic
changes secondary to (1) long-term chronic cannabis use, and (2) acute into
xication due to cannabis smoke or injection of delta-9-tetrahydrocannabinol
(Delta(9)-THC) solution. A comprehensive review of the neuroimaging litera
ture was performed. To further interpret and understand this research, lite
rature addressing animal receptor and neurochemical models were also survey
ed. Neuroimaging findings have concluded that abstinence from smoking resul
ts in depressed cerebral metabolism in chronic users, while acute exposure
reverses this condition, producing higher cerebral blood flow in chronic us
ers compared to controls. These changes are hypothesized to be associated w
ith alterations of cannabinoid receptors secondary to chronic exposure. Fin
dings from animal models are consistent with the proposition that adaptatio
n to chronic exposure results in adjustment of normal neurotransmitter leve
ls. The frontopontocerebellar network is implicated as a site sensitive to
cannabinoid-induced alterations in the levels of dopaminergic activity deri
ved through the medial forebrain bundle, which projects from the ventral te
gmental area. This network is involved in the modulation of a range of huma
n behavior that is clearly altered by use of cannabis. The combined neuroim
aging and animal data suggest that metabolism of component regions of the f
rontopontocerebellar network are altered by acute and chronic exposure to c
annabis through modulation of both the cannabinoid and the dopamine system.
Copyright (C) 1999 John Wiley & Sons, Ltd.